Web site Maximum PC describes how to add the latest service pack and a few drivers (like RAID or SATA drivers) to your original Windows CD to speed up the process of a Windows installation.

Although Vista is the way of Windows future, most of a us will be on XP for at least a little while longer. Next time you need to install or re-install Windows XP, this method should help you do it as quickly and painlessly as possible. It's somewhat of a complicated process, but the article breaks it down into detailed steps, so almost anyone should be able to do it. For another take, you might want to check out the unattended Windows install.